Dies for cutting threads.



M. H. LUKBNS.

DIES FOR CUTTING THREADS.

APPLICATION FILED JUN 20, 1911 4 1,020,996. Patented Max-26,1912.

2 SHEETS-BBBET 1.

PI itr gssss: li qgz mr;

QMKLM 2mm, 9%. cum] M. H. LUKENS.

DIES FOR CUTTING THREADS.

AYPLIUATION FILED JUNE 20, 1911.

1,020,996. Patented Mar. 26, 1912.

2 SHEETBBHBET 2.

m Byhis/Rforney, ean i the desired thread being known the pivot pins D D are withdrawn and the dies G C rotated until the proper thread surfaces are opposite each other when the pivot pins D D are forced tightly into place, securing the dies C C in the proper position by means of the keys d d. The device is now placed upon the piece to be cut in the position shown in Fig. 2 and the centering plate rotated until the jaws H H H come in contact with it. By means of the threaded handles a a, the dies are brought into cutting position, care being used to have the horizontal center line of the handles at right angles to the piece to be threaded. The threading operation may now be proceeded with in the usual manner, forcing the dies together by the use of the threaded handles as may be necessary.

"When the cutting edges of the dies become dulled from use, it is only necessary to grind the flat surfaces between the threaded surfaces to restore the sharp cuttingedges to condition for use.

WVhen threads are to be cut on quite small rods or pipe the dies C are constructed as shown in Fig. 7, in which case they are made much deeper, and only a portion of the thickness devoted to the threaded surface, the lower portion being formed in concave surfaces 6 e of the same radius as the bottom of the thread of the threaded portion, thus providing ample support and rendering the centering device described above unnecessary. I

To adapt my device for use in a machineoperated by power I provide the mechanism shown in Fig. 10. The piece E to be threaded is shown held in an ordinary chuck K of a lathe. Fixed upon the rear spindle L is the die supporting frame M, to which is fixed the side bars N corresponding to the frame A, Figs. 1 and 2 and carrying the die holders B B which, with the dies C C are constructed in the same manner as before described. The dies are adjustable to or from the center by means of the set screws P P, in a similar manner to that used in the hand device by the handles a a.

To render the change of the dies from one pitch of thread to another more convenient the pivot pins D D are provided with much shorter keys cl (Z, and upon their inner ends are placed the spiral springs n a, secured by the washers p p, by which construction the pivot pins may be withdrawn a short distance, the dies rotated to the desired positions, and the pins, upon being released are drawn into place by the action of the springs 11. a.

What I claim and desire to secure by Letters Patent is:

1. The combination of two rotatable thread cutting dies centrally pivoted to silding blocks placed opposite each other, said dies adapted to out two or more threads of different pitches, and having two or more keyways cut around their central holes, pivot pins for pivoting said dies and having tapering keys fixed thereto and adapted to enter said keyways, with sliding blocks one portion of which is above and one portion below said dies, and having two or more keyways cut around the central hole and adapted to receive said pivot pins and their taper keys, and a frame adapted to receive and support said sliding blocks and to adjust them to and from each other by threaded handles forming a part thereof, substantially as described and for the purposes set forth.

2. In a thread cutting device adapted to,

be operated by hand or power, and consist ing essentially of two rotatable thread cutting dies centrally pivoted to sliding blocks placed opposite each other, the combination of two or more tapering keyways cut around their central holes, pivot pins for pivoting said dies and having tapering keys fixed thereto and adapted to enter said keyways, and a frame adapted to receive and support said sliding blocks and to adjust them to and from each other, substantially as and for the purpose described.

MILTON H. LUKENS.

VVit-nesses OSCAR E. Pnrmreo, HILDA A. LUNDBERG.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

